Methods and devices of imaging and biopsy

ABSTRACT

Certain embodiments include an endoscope and methods for imaging using the endoscope. The endoscope may include an imaging channel and a tip positioned at one end of the imaging channel, the tip adapted to collect light from a field of view that extends 360° around at least a portion of the endoscope and to transmit the light to the imaging channel. Certain embodiments may also utilize various sensors, controllers and processing mechanisms to record and process images into a representation, move the endoscope in and out of the endometrial cavity, and to biopsy a portion of the endometrium.

This application is a continuation application of U.S. application Ser.No. 12/493,036 filed Jun. 26, 2009, which application was a continuationof U.S. application Ser. No. 10/785,802 filed Feb. 24, 2005 whichapplication claimed priority to U.S. provisional patent application No.60/450,224, filed 10 Feb. 26, 2003. The disclosure of U.S. patentapplication Ser. No. 10/785,802 and U.S. provisional application No.60/450,224 is hereby incorporated by reference

FIELD OF INVENTION

This present invention relates to methods and devices for imaging and/orbiopsy.

BACKGROUND

A common practice in gynecology is for a woman to have an annualexamination including speculum and bimanual examination and aPapanicolau smear (which primarily screens for cervical cancer). On theother hand, there is no current screening test for endometrial cancer,the most prevalent form of gynecological cancer. Therefore imaging andbiopsy is usually delayed until after symptoms develop. Patients withendometrial carcinoma or hyperplasia typically exhibit increased orirregular menses or postmenopausal vaginal bleeding (PMB). The standardof care as recommended by the American College of Obstetricians andGynecologists is for patients with these symptoms to undergooffice-based endometrial biopsy (EMB) and endocervical curettage (ECC).The EMB is a blind biopsy done typically with an endometrial Pipelle™.The Pipelle™ is a disposable plastic tube measuring approximately 3.1 mmin diameter with an internal plunger which is drawn back to create asmall amount of suction once the device has been introduced into theendometrial cavity via the cervix. By moving the device in and out, asample of endometrial tissue is removed for histologic examination.

None of the above techniques use imaging of the endometrium. There arecurrently two imaging modalities that are available. The first istransvaginal ultrasound, which may be useful in screening patients withPMB for endometrial cancer. The other technique for imaging theendometrium is hysteroscopy. Not surprisingly, using the hysteroscopefor image-guided biopsy has been shown to be superior to the above blindprocedures. However, the majority of gynecologists do not performhysteroscopy. In addition to the issues of pain, invasiveness, andmorbidity, there is a steep learning curve. In addition, the use of adistending media, for example, saline or a gas (e.g., CO2) to createopen space in the uterus, may lead to problems. In addition, because thehysteroscope can only image the tissue in front of it, experience andmanual dexterity are required in order to examine the whole endometrium.

SUMMARY

Certain embodiments of the invention relate to methods and devices usedfor imaging a body system, including the endometrial cavity.

One embodiment relates to methods for imaging an endometrial cavity,including positioning an endoscope at least partially within theendometrial cavity, and imaging tissue within the endometrial cavityaround a circumference of at least a portion of the endoscope.

In one aspect of certain related embodiments, a method as describedabove may also include obtaining a plurality of images of theendometrial cavity by moving the endoscope through at least a portion ofthe endometrial cavity and imaging tissue around the circumference of atleast a portion of the endoscope at a plurality of positions within theendometrial cavity. Such a method may also include storing the pluralityof images, and processing the images with an image data processingsystem to create at least one representation of at least a portion ofthe endometrial cavity.

Certain embodiments also relate to a method including positioning atleast a portion of an endoscope within the endometrial cavity, obtainingan image of tissue in the endometrial cavity extending 360° around atleast a portion of the endoscope, and moving the endoscope within theendometrial cavity to obtain a plurality of images each extending 360°around at least a portion of the endoscope.

In one aspect of certain related embodiments, a method such as thatdescribed above may further include determining an area of interestbased on the images. In addition, such a method may also includeperforming a biopsy in the area of interest based on the images.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the invention are described with reference to theaccompanying drawings, which, for illustrative purposes, are notnecessarily drawn to scale.

FIG. 1 is a schematic of an embodiment of an imaging apparatus thatallows for omni-directional viewing. Light is collected at theomni-directional tip (1) and is transferred to the imaging channel (5)with the appropriate detector.

FIG. 2 is an illustration of an embodiment of an omni-directional tip(6) collecting light from all directions. Light (8) entering the tipwill be transferred into the endoscope body portion (7).

FIG. 3 is a schematic of an embodiment of an omni-directional tip. Usinga reflecting medium, such as a mirror, the light within the displayedfield of view (12) aimed at the perspective point (11) will be reflectedoff of the tip (10) and imaged through the endoscope (13).

FIG. 4 illustrates how light is reflected off a reflective surface inthe field of view in accordance with an embodiment of the presentinvention. Any object within the field of view (12) will project lightoff the mirror or other reflective surface (10) into the image transferoptics of the endoscope.

FIG. 5 is a schematic of another embodiment of an omni-directional tip.By refracting the light through the use of a lens element (16), lightwithin the field of view (18) aimed at the perspective point (17) iscaptured into the endoscope (19).

FIGS. 6( a)-(d) illustrate embodiments of an illumination system incoordination with a reflective element imaging system.

FIG. 7 shows an illustration of how an embodiment of the apparatus maycapture images of the endometrial cavity. The endoscope (29) is attachedto a position sensor (38). By changing the position of the endoscope,with the position sensor, the imager (35) will be exposed to differentareas of the endometrial cavity (31). Through this means, in asystematic fashion, all areas along the length of the cavity may becaptured.

FIG. 8 shows a preferred embodiment of an image collection process. Theendoscope (42) will transverse through the endometrial cavity (43)through several positions (44). Through the use of the position sensorsetup (45), the positions within the endometrial cavity (43) willcorrespond to segments (46) of the complete single endometrial map (47).

FIG. 9 shows a preferred embodiment of a position sensor apparatus. Theendoscope (48) is attached to a linear track (49) with a bi-directionaloptical encoder (50). As the endoscope moves along the track, theoptical encoder will detect changes in position. Therefore the positionsensor controller (51) will know at what position the endoscope is atand trigger the detector (53) when the endoscope is at an establishedlocation.

FIG. 10 shows an illustration of how an embodiment of the apparatus mayprocess the images. The omni-directional image (57) is dewarped (60 to62) and used to generate a single endometrial map (63).

FIG. 11 shows an embodiment of a biopsy apparatus. Once an area oftissue has been identified by a clinician as being of concern (64), thesame position sensory system (66,67) can be used to position the biopsyapparatus to the area (64). Tissue samples will be gathered with thecollector apparatus (69). Suction created by pulling the plunger back(70) will pull the tissue samples into the cylindrical lumen (68) withinthe device for histologic testing.

DETAILED DESCRIPTION

Certain embodiments of the present invention pertain to minimallyinvasive imaging and biopsy systems and methods used to identifypathology of an organ system such as the uterus. In one preferredapplication/embodiment, endometrial imaging is described. Theendometrial cavity may be defined as the endometrial lining and/or anypathology detectable from the surface of the endometrium within theuterus. Imaging may be defined as collecting electromagnetic rays andcreating at least a two dimensional representation of an object. Certainembodiments include an omni-directional (360°) viewing endoscopecontrolled by a position sensor mechanism to produce images of theendometrial cavity for visualization of tissue and pathology that isdetectable within the cavity. Certain embodiments may also includeimaging devices such as, for example, full color CCD, spectralmulti-wavelength (including visible, infrared, and ultraviolet, imagingtechnology, or other electrical transducer to produce a detailed visualmap of the endometrial cavity in order to assist the clinician inidentifying uterine pathologies.

Certain embodiments of the present invention also integrate an apparatusfor directed biopsy, accomplished using a position sensor system. Usingposition tracking, the coordinates of the area of interest from imagingsystem can be translated back to the physical location within theendometrial cavity. Such embodiments augment conventional biopsy with adetailed 360°, omni-directional view of the endometrial cavity aroundthe endoscope, thereby decreasing the need for manual dexterity. Suchembodiments may be used as a minimally invasive tool for identificationand directed biopsy of uterine or other organ pathology.

As noted above, certain embodiments of the invention relate to methodsand apparatus for imaging and sampling tissue from the endometrialcavity.

In accordance with certain embodiments, in order to image the tissuewithin the endometrial cavity (or organ cavity), a specialized endoscopeis used. As seen in the embodiment illustrated in FIG. 1, an imagingapparatus includes a rigid or flexible endoscope (3), an illuminationchannel (4), and an imaging channel (5). A camera, electrical transduceror other imaging technology may be attached to the imaging channel (5)to capture images. The endoscope contains a body portion (3 a) thatsurrounds at least a portion of the imaging channel of the device. Oneaspect of the imaging apparatus is the omni-directional tip (1) thatwill allow it to visualize 360° of the endometrial cavity perpendicularor near perpendicular to the optical axis (2) at a position in theendometrium at or adjacent to the tip. The omni-directional tip may alsobe positioned a distance away from an end region of the endoscope. Theendoscope is preferably positioned transcervically to the uterinefundus. As the apparatus is introduced or retracted, images of theendometrial cavity can be captured as the tip of the scope passesthrough the cavity.

As seen in FIG. 2, any light (8) collected at the omni-directional tip(6) will be imaged into the endoscope body portion (7) and transferredto an imaging sensor on the other end of the endoscope. To illuminatethe field of view, fiber optics may be used. Fiber optic lightconductors may be mounted coaxially around the image channel of theendoscope, much like standard endoscopes. This allows for transmissionof light from an illumination channel (see FIG. 1 illumination channel4) to the omni-directional tip, where the light can be directed to thefield of view and therefore illuminate the tissue that will be imaged.Unlike some conventional imaging methods in which imaging is done infront of the endoscope tip with a limited field of view using liquid orgas distention, (as done in conventional hysteroscopy and relatedimaging), certain embodiments image the endometrial cavity coapted 360°around the tip, perpendicular or near perpendicular to the optical axis(2). Such device will capture the images of tissue and collect apanoramic view (360° view). When the endoscope is retracted/insertedthrough the cavity, as described below (FIG. 8), the successive viewsthat are formed can be combined into a collage of all the images.Therefore a full image of all the views can be combined displaying theentire length of the endometrial cavity.

The ability of the imaging apparatus to capture light from 360° at theomni-directional tip is illustrated in multiple embodiments. FIG. 3shows a schematic of one embodiment of an omni-directional tip. Thismethod includes an omni-directional tip that uses a reflective element(10), such as a mirror to image the surrounding tissue. The shape of thereflective element used in this embodiment can vary depending on thesubsequent image processing that will be used to un-warp the collectedimage. Any light within the field of view (12) that can create an imagewill pass through a window (14) on the tip. The window (14) maypreferably made from a clear material such as plastic, acrylic, glass orsome other clear substance. The image is reflected into the endoscopebody portion (13) to be imaged by a sensor at the imaging mount of theendoscope (See imaging mount 5 in FIG. 1). An optional element can beattached to the tip of the endoscope. An example of such an element isan end cap structure (80). The end cap structure may take a variety ofshapes, for example a convex shape such as that shown in end cap (80) inFIG. 3. Such an end cap may facilitate insertion and removal of theendoscope. Through this embodiment, the imaging tip will collect imagesof tissue that are within the field of view (12)—tissue which is 90°with respect to the optical axis, and further behind the tip. FIG. 4illustrates the embodiment further. Any light originating within theendoscope's field of view (12), will be reflected off the reflectiveelement (10), and transferred through the endoscope to the imagingdetector.

Another embodiment of an omni-directional tip is shown in FIG. 5.Instead of a reflective element as before, this embodiment uses a lensor a system of lenses (16) to refract the light into the endoscope. Allthe light that can form an image within the field of view (18) will berefracted into the endoscope body portion (19) and transferred to theimaging sensor at the imaging mount of the endoscope. Using a lenselement (16), this embodiment captures images of tissue within the fieldof view (18) that differs from the field of view (12) in the embodimentillustrated in FIGS. 3 and 4. In the embodiment illustrated in FIG. 5,the field of view (18) includes tissue that is in front and tissue thatis oriented up to 90° with respect to the optical axis. As seen in theembodiments in FIGS. 3 and 5, at least a portion of the field of view((12) in FIG. 3 and (18) in FIG. 5) extends around a circumference of aportion of the endoscope and thus an image including tissue extendingaround a circumference of the endoscope may be obtained.

By combining the omni-directional tip with a method for illuminating thefield of view from the illumination brought in by the fiber opticsmounted coaxially around the endoscope, an embodiment of the imagingsystem can be established. FIG. 6 illustrates an embodiment of theinvention using a reflective element to illuminate the field and areflective element to image the field. This embodiment includes a moredetailed view of an omni-directional tip (21) including a reflectiveelement (22) similar to the reflective element (10) illustrated in FIG.3. Looking at a cross section of the endoscope's (20) omni-directionaltip (21) and region adjacent thereto in the blown up portion of FIG. 6,this embodiment uses fiber optics (25) that are mounted coaxially aroundimaging optics (26) to illuminate the field of view (23). Light passingthrough the fiber optics (25), will reflect off a reflecting element,such as a mirror (24) to illuminate the field of view (23) by crossingthe optical axis, as illustrated in FIG. 6( b), which shows a generalschematic of this embodiment illustrating a methodology of illuminatingthe field of view (23). In parallel with this, as illustrated in FIG. 6(c), the imaging system collects light (indicated by lines and arrows)from the field of view (23) and delivers the light towards the endoscopeoptics (26). An alternate embodiment of the system is shown in FIG. 6D.This embodiment uses the illumination coming from the coaxial fiberoptics (25) and reflects the light off the imaging mirror (22) toilluminate the field of view (23). In both embodiments, through the useof the endoscope optics (26), the image is transferred to a detectorconnected at the end of the imaging channel (5). Nonuniform illuminationthat may be caused by fiber optic illuminators that are mountedcoaxially around the endoscope is corrected subsequently by softwareonce the image acquisition has been completed.

An example of the operation of an imaging apparatus in accordance with apreferred embodiment of the present invention is demonstrated in FIG. 7.A systematic method for tracking the position of the endoscope tip isused in this embodiment. This can be accomplished by a position sensor.The position sensor (38) and the controller (39) will control or trackthe position of the preferably rigid endoscope body portion (29) withthe omni-directional tip (30) in order to capture information fromendometrial cavity (31). Therefore, as each image is captured in orderto use each image to describe a portion of the endometrium, the physicallocation of the tissue imaged in each capture will be monitored. Theomni-directional viewing tip (30) is positioned to image the tissue.Illumination generated by a light source (32) is inputted into theapparatus's illumination channel (33) on the endoscope. The illuminationtravels through the endoscope and illuminate the field of view througheither the omni-directional tip (30) or another reflective or refractiveelement. The light reflects off the endometrial cavity (31) that issurrounding the tip and be collected back into the endoscope's imagingchannel (34) through use of the omni-directional tip. The output of theimaging channel (34) travels to the imaging sensor (35) that is mountedon the endoscope. Digital images of the light is captured with the useof the imaging sensor (35) and computer (36) and its relevant imageacquisition. The images that are captured are stored on the computer(36) for processing and displayed on a monitor (37) for observation bythe user after the processing is complete. Embodiments may also includeone or more lenses (85) positioned at various locations within the bodyportion (29) of the endoscope.

By positioning filtering elements within the optical path of theembodiment, specific wavelengths of light are imaged. Through the use ofwavelength specific imaging, functional information about tissuephysiology can be captured. A number of embodiments of this are shownwithin FIG. 7. A first method can be visualized by placing a filteringelement at position (41) where the illumination light is limited to aspecific bandwidth determined by the filtering element. Therefore allthe light that illuminates the field of view is filtered and the lightthat is imaged through the imaging channel (34) is of specificwavelengths. A second method can be accomplished if a filtering elementis placed at location (40). The tissue is illuminated with broadbandlight from the light source (32), and the light coming back through theimaging channel (34) is not limited. However, the filtering element atposition (40) fillers the light just before it is imaged by the imager(35). Therefore, only light of a particular wavelength is captured.Using either method, the filtering element allows for selective imagingof light. In addition, certain embodiments may utilize fillers at bothlocations 40 and 41 or even at different locations if desired. Byselecting the correct filler characteristics and location(s), any light,whether in the ultra-violet, visible or infrared spectrum, can beimaged.

FIG. 8 illustrates a method embodiment for imaging the entireendometrial cavity using the endoscope such as that illustrated in FIG.7. Once the endoscope tip (30) is in position within the endometrialcavity (31), it can begin image acquisition. After an image is capturedat one location, through the use of the position sensor (38) andcontroller (39), the endoscope tip (30) will be repositioned to the nextposition within the cavity. An image is captured at the new location andthe endoscope is moved again. As the endoscope tip (30) moves throughall the positions y₁, y₂, . . . (44), it will capture all the images inseries. Once all images have been captured, the image acquisitioncomputer will perform image processing on the collected images togenerate a single 2-dimensional map of the imaged region (47). Thepositioning sensor system (45) keeps track of all positions that theimaging apparatus acquired and maintains a single coordinate system forthe 2-dimensional map. This allows the position sensor to translate anyposition (46) on the 2-dimensional map to a position (44) within theendometrial cavity (43). This allows a user the ability to select anarea of concern and then return to that location for biopsy.

A position sensor may synchronize with an imaging sensor such thatimages are captured at specific positions. This allows for fixedintervals between each image acquisition. One embodiment of an apparatusis shown and described in FIG. 9. FIG. 9 illustrates an endoscope (48)mounted on a linear track (49) so that it can be inserted and retractedalong a single axis of motion. The motion of the endoscope (48) ineither direction on the track is detected through an optical encoder(50) that is part of the embodiment. This optical encoder (50) ispreferably bi-directional. The optical encoder (50) which is used withservomotors and robotic actuators, is able to detect changes inposition. The optical encoder (50) is comprised of a round disk (54)with a number of holes (77) extending close to and around the outsideedge of the disk and a pair of photo-diode detectors (55). As theendoscope moves along the track, the disk is spun by the motion. Thepair of photo-diode detectors are mounted such that the disk (54) blocksthe space between the diode and detector. When one of the holes (77) inthe disk lines up with the photo-diode detector (55), the detector isable to detect the light from the photo-diode and outputs a signal. Asthe wheel turns, a puke pattern is outputted (56) from the photo-diodedetector that corresponds to the passing of each of the holes (77) inthe disk. The holes (77) are preferably evenly distributed on the disk.As there are a known number of holes, the total distance that the wheelmoved can be determined—which indicates the distance the endoscopemoved. By using two of these photo-diode detectors, the sensor is ableto detect the direction of the motion as well.

The position sensor controller (51) illustrated in FIG. 9 detects thesechanges from the signals that it is receiving from the optical encoder(56). Through this information, the controller has an accurate measureof any distance the endoscope traveled along the track. This allows thecontroller to trigger the detector (53) to capture the light (52) thatis being imaged by the endoscope. This embodiment allows the device toknow exactly how far apart each image in an image series was captured.Additionally, this allows the controller to set the position intervalbetween each image captured.

The image series captured through the use of the apparatus containsvisual distortions because of the omni-directional tip (either becauseof the mirror or the lens system). Each of the images has acharacteristic ‘fish-eye’ distortion that needs to be corrected. Giventhat the distortion in the images is created by a known source (the lensor mirror at the endoscope tip), the distortion can be removed throughsoftware and image processing. This allows the device to collecttogether undistorted segments of the tissue and combines them into asingle 2-dimensional map. This processing is accomplished throughsoftware after the image series has been acquired.

FIG. 10 illustrates an example of the concept of dewarping the series ofimages. A single image (57) may contain ‘fish-eye’ distortion because ofthe shape of the omni-directional viewing tip. In order to unwarp theimage, a ring-like segment of the image is selected centered at thevanishing point in the middle of the image (58). The size or thicknessof this ring is dependant on the distance the endoscope tip was movedbetween successive images and the resolution of the images.

Once the ring segment has been identified, the ring segment (59) isclipped out of the overall image for dewarping. Using a transformationbased on the shape of the omni-directional viewing tip, the segment canbe dewarped through steps (60, 61, 62) into a standard rectangular form(62). However, given that the thickness of the ring segment willpreferably be small (in order to maintain high resolution in theendometrial map), in most embodiments, several segments from successiveimages (n, n−1, n−2, . . . ) will need to be combined or stackedtogether to form an overall single map (63). Therefore, as the imageprocessing moves through the series of images, visual information aboutendometrial cavity is segmented out and the final endometrial map isbuilt segment by segment. By taking advantage of the position sensorsystem (such as that illustrated in FIG. 8) and stacking the imagesegments one next to another (63), the apparatus is able to create ananatomically scale stack of ring segments (59). Therefore, the ‘stacked’image contains anatomical information without the image warping seen inthe initial image (57). Once through all the images in the imagesegment, a complete map has been generated, displaying the visualinformation that the apparatus collected in its procedure. The map maybe of use to the physician, as it allows the user to see within theendometrial cavity or organ cavity and examine the tissue lining forareas of concern, polyps or other pathology.

In another aspect of certain embodiments, a biopsy apparatus has theability to be used in conjunction with the imaging apparatus. Thetechnique for biopsy, whether it is performed through optical means(spectroscopy, optical coherence tomography, etc), or physical means,can be accomplished. An embodiment of physical biopsy is shown in FIG.11. Once a clinician has identified an area of tissue, that area ofconcern (64) may be biopsied. Once the area of concern (64) in theregion (65) has been identified through the use of the imagingapparatus, a positioning sensor system (66,67) is able to use the samecoordinate system used in the image processing algorithms and allow forthe positioning of the biopsy apparatus over the area of concern (64).The embodiment uses the position sensor (66) and positioning controller(67) to position a collecting tip (69) at the area of concern (64). Thetissue is scraped using the collection tip (69) to obtain a tissuesample. Suction is created within a cylindrical lumen (68) inside of theapparatus through the use of a plunger on the other end (70). Thesuction draws the sampled tissue into the lumen (68), where it is storeduntil the apparatus is retracted out of the body and the tissue canundergo histological analysis. Other methods for obtaining biopsysamples may also be utilized.

As set forth above, certain embodiments use and/or relate to anendoscope including an imaging channel and a tip positioned at one endof the imaging channel, the tip adapted to collect light from a field ofview that extends 360° around at least a portion of the endoscope and totransmit the light to the imaging channel. Certain embodiments may alsoutilize various sensors, controllers and processing mechanisms to recordand process images into a representation, move the endoscope in and outof the endometrial cavity, and to biopsy a portion of the endometrium.Other aspects and features described above may also be used in certainembodiments.

It is, of course, understood that modifications of the presentinvention, in its various aspects, will be apparent to those skilled inthe art. Additional embodiments are possible, their specific featuresdepending upon the particular application. For example, other dataprocessing and representational methods (for example, a threedimensional representation) may be used instead of or in addition tothose discussed above. In addition, certain embodiments may beapplicable to other organ systems in addition to the endometrium,including, for example, the gastrointestinal tract.

1. A method for imaging an endometrial cavity, comprising: positioningan endoscope at least partially within the endometrial cavity; andimaging tissue within the endometrial cavity around a circumference ofat least a portion of the endoscope.
 2. A method as in claim 1, furthercomprising: obtaining a plurality of images of the endometrial cavity bymoving the endoscope through at least a portion of the endometrialcavity and imaging tissue around the circumference of at least a portionof the endoscope at a plurality of positions within the endometrialcavity; storing the plurality of images; and processing the images withan image data processing system to create at least one representation ofat least a portion of the endometrial cavity.
 3. A method as in claim 2,further comprising displaying the at least one representation to aviewing device.
 4. A method as in claim 2, further comprisingilluminating the endometrial cavity and acquiring the light radiatingfrom the endometrial cavity.
 5. A method as in claim 2, furthercomprising performing the imaging of tissue around the circumference ofat least a portion of the endoscope in the absence of distending mediain the endometrial cavity.
 6. A method as in claim 2, where the systemalleviates the experience or skill required from the user commonlyneeded for hysteroscopy in order to image the endometrial cavity.
 7. Amethod as in claim 2, wherein the endoscope includes at least one of areflective element and a refractive element.
 8. A method as in claim 7,further comprising performing the imaging using a specific wavelength ora specific bandwidth of light.
 9. A method as in claim 7, furthercomprising performing the imaging using at least one of visible,ultra-violet and infrared wavelength light.
 10. A method as in claim 7,further comprising performing the imaging using at least one ofreflected imaging, scattered light imaging and florescence imaging ofthe endometrial cavity.